Responsibility for a task is defined by setting its assignment. You can do this by selecting a User Task and clicking its Assignments property. A dialog pops up that allows you to choose whether the assignee should be a single person (it can be a named user, or simply the person that started the process); a list of candidate users; or, one or more candidate groups. If a task is assigned to a list of candidates or groups, then someone from the list or group has to claim the task to work on it – it then becomes directly assigned to them for that specific task in that specific instance of the process.
I created the workflow signed in as admin user and then in the Task app started the process logged in as the same admin user.
The admin user is by default present and I have not assigned it to any group
Got the issue. There was nothing wrong is the user assignment but the issue was that I was not deploying the app after doing changes in the workflow. After deploying the app now the assignment works just fine.
I guess the app needs to be deployed(publish) every time any change is done so then only the same will be reflected in the task app.
Actually, I am not sure what defines a new version but what I experienced is that after doing any change you need to publish the app to see the changes reflected in the Task App.
As the task is assigned to one person only so no claim button is needed. Instead, the save and complete button are working as expected.
Actually that demo I completed. I was working on another demo which is a little below that: vacation request app which does not have any user group so no claim button will be present but just the complete button as the task is assigned to the initiator itself.